


Sharing

by The_Winter_Writer



Series: Bingo Challenge [13]
Category: Marvel Cinematic Universe, The Avengers (Marvel) - All Media Types
Genre: Alpha Steve Rogers, Alpha rut, Alpha/Beta/Omega Dynamics, Barebacking, Beta Bucky Barnes, Birth Control, Bottom Tony Stark, Bucky Barnes & Steve Rogers Friendship, Butt Plugs, Come Inflation, Consensual Partner Sharing, Established Bucky Barnes/Tony Stark, Healthy Relationships, Knotting, M/M, Non-Traditional Alpha/Beta/Omega Dynamics, Omega Tony Stark, POV Tony Stark, Rough Sex, Rut Sex, Steve Rogers & Tony Stark Friendship, Top Steve Rogers
Language: English
Status: Completed
Published: 2018-01-22
Updated: 2018-01-22
Packaged: 2019-03-08 07:18:00
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,510
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13453215
Author URL: https://archiveofourown.org/users/The_Winter_Writer/pseuds/The_Winter_Writer
Summary: It wasn't a conventional relationship by any stretch of the imagination but it worked and Tony wouldn't trade it. Tony didn't mind that Bucky sometimes shared him with his best friend, Steve, outside of Heats and he didn't mind helping Steve through a tough Rut.





	Sharing

**Author's Note:**

> Wow it took me awhile to get this one out. This is a follow-up to 'All Options' set a few months later because I hated all of the other ideas I came up with for this bingo square and I realized a follow up for 'All Options' worked perfectly. You don't have to read the first fic, this can be a stand alone, but it might make a bit more sense.
> 
> My thirteenth bingo square in my quest for a W-shaped bingo is O4: Consensual Partner Sharing. This square is the reason I tagged Steve/Tony first and Bucky/Tony second. Bucky/Tony is established and Bucky is sharing Tony with Steve in this fic (which is what the focus of this fic is).

Tony occasionally found himself pinned under Steve, knot firmly locked inside of him, as his mate’s best friend rocked up against him and moaned his appreciation. Despite the countless times that Bucky had shared him with Steve this was the first time he’d done _this_. Sure Steve had helped him a few times with his Heat when Bucky wasn’t able but Tony had never helped Steve through a _Rut_.

He found himself pulled in for a soft, lingering kiss to his lips and then one to his forehead.

It was soft and sweet.

Tony had no idea how he’d gotten so lucky. Theirs wasn’t a conventional mating by any stretch of the imagination, Omegas belonged with Alphas and Bucky was a _Beta_ , but he didn’t regret it. He didn’t mind that Bucky willingly shared him with Steve outside of Heats.

They were best friends, practically brothers, and Tony was fine with being shared occasionally. He actually _liked_ Steve. Tony felt nothing but affection for his mate’s best friend and it had the added bonus of making two people pleased with him at the same time.

“Steve said he’d have everything you might need.” Another kiss, “I love you, Sweetheart.”

“Love you too.”

Then Bucky was gone and Tony toed off his shoes after locking the door. His change of clothing was left in a bag by the door, it wasn’t like he’d need it for days, before he started moving towards Steve’s bedroom. He’d been at Steve’s enough times to know where everything was located.

His clothing came off, piece by piece, as he moved further and further into Steve’s home. The thick, heady scent of Alpha Rut saturated the air. He could catch notes of others, some lingering ones of Alpha/Omega sex and the unmistakable twang of arousal, but Steve’s Rut was almost overwhelming.

Tony’s ass clenched in reaction and he could feel his body practically flood his channel with slick in preparation. His muscles were loosening, _biology at its finest_ he thought, before he turned the door knob and stepped into Steve’s bedroom completely naked.

The only thing with him was the plug he’d inserted before leaving the house he shared with Bucky.

Steve’s bright blue eyes had bled Alpha red and Tony watched as they zeroed in on him with an almost predatory kind of intensity. The sight had a whine escaping him without thought. He tilted his head in a show of submission he’d long since learned was best when dealing with an Alpha in Rut.

It took seconds for Steve to close the distance and Tony was shoved back against the door. Strong hands rested against the backs of his thighs before Tony found himself lifted and pinned. Fingers moved back, pulled the plug out and let it fall, as the hard length of Steve pressed up against him registered.

Tony could feel his face flushing with arousal as Steve’s pheromones flooded his senses and without a second of delay Steve was shoving up into him with a low snarl. It was more than obvious this was an unnaturally strong Rut.

His hands gripped at Steve’s overwarm body and a choked off moan escaped when Steve slammed balls deep, hands holding him in place, before he started to rapidly fuck up into Tony with a single-mindedness that only an Alpha could achieve.

“Fuck.” Tony’s throat worked and his heart pounded as pleasure lit up inside of him. There was something almost primal about being at the mercy of an Alpha lost to Rut. This was especially true about a strong Alpha who was typically far more composed.

Steve fucked and fucked and fucked all the while the only thing Tony could do was hold on, body trembling and breathing turning shuddery, as his orgasm coiled inside of him.

“Feel so good.” Steve groaned against him, “So fucking good.”

The primal part of Tony’s brain _preened_ at the compliment. It loved the way Steve had manhandled him, held him in place and took him roughly against the door. They hadn’t even made it to the bed.

Now Steve’s knot was catching on his rim, tugging and popping free, until Steve’s hold shifted and he ground himself up against Tony’s ass with a low snarl.

Pleasure slammed into him, stealing his ability to think and everything seemed to white out, as Tony moaned. Distantly he could hear Steve moaning and he could feel a thick Alpha knot caught inside of him as his inner muscles immediately set to work milking Steve’s knot.

“Mmmmm.” Steve was nuzzling against him, emptying his release into Tony, while he rocked up against his ass. “So good.” The words were practically pleasure slurred, “Good Omega such a good Omega.”

His back left the door. Steve easily carried him across the room and settled down in a large, plush chair. Tony’s knees settled on both sides of Steve and a groan escaped when Steve’s knot tugged on his rim when Steve shifted them into a more comfortable position.

“Feel better, big guy?” Tony asked the second he could focus past the haze of pleasure and the way his instincts were purring at being caught on an Alpha knot.

He locked eyes with Steve and could see how _some_ of Steve’s instinct to knot an Omega was calmed. At least for the moment. “Tony.”

“Who else smells this good?” he teased. The affection that was always there around Steve bloomed in his chest along with the need to tease relentlessly. “Feel a little more yourself?” he hoped so. Tony knew how badly it sucked to be lost to instinct while desperately needing relief that only a partner could provide.

Steve nodded and then frowned at him, “I didn’t hurt you, did I?”

“Nope.” Tony popped the P and shifted on Steve’s lap so he was a bit more comfortable. He wasn’t going to be walking when Steve’s knot finished because there wasn’t a question that his legs were going to fall asleep after maintaining this position for the duration of a knot. “You’ve fucked me harder.”

Tony had walked a bit gingerly on several occasions that Bucky had shared him with Steve and Steve had been a bit more enthusiastic. It was probably, mostly, because Steve’s cock was a monster and he had a knot to match.

His words didn’t do anything though and Steve immediately started looking him over. Once he seemed satisfied he leaned his head back and his eyes fluttered closed. Tony took in the flush of pleasure staining Steve’s cheeks and the way his chest rose.

By the end of Steve’s Rut he knew he’d be a picture of marks and bruises. No Alpha during a Rut managed to not leave some kind of mark. Tony doubted Steve would be an exception.

Tony was looking forward to Bucky pampering him when Steve’s Rut finished and he was back home. He shifted and moved so he could rest his cheek against Steve’s chest. It was better to get comfortable because Steve’s knots always lasted awhile.

* * *

On the third day Steve was completely and fully lost to instinct. He’d long since slipped into breeding talk, into happily playing with Tony’s exhausted body and greedily fucking Tony into the mattress while Tony simply whined or moaned under him.

His ass was sloppy, his hole seemed to be permanently loose and his muscles trembled whenever he attempted to assume the preferred position for an Omega: face down and ass raised up without help.

Steve’s large hands hauled him up from where he was sprawled out in the center of Steve’s bed, knocked his knees wide apart and made sure his ass was at the perfect height. The hands on him left for a few seconds and then the wide head of Steve’s cock pushed against his ruined hole before sinking in effortlessly.

The ringing slap of skin on skin immediately started to fill the room along with Steve’s grunts, the low groan of the mattress and the filthy sound of a cock plowing through a sloppy hole.

Tony flushed, almost embarrassed at how thoroughly he’d been used, as his own pleasure started to burn in his gut. He knew this was nothing, the blurred memories and haze of pleasure from the glory hole were a testament to that, but he was completely aware of everything now.

Fingers dug into his hips and yanked him back to meet each of Steve’s hard, fast thrusts as Tony’s fingers curled in the sheets and his mouth fell open.

Whines, whimpers, gasps and moans spilled out of his mouth. He was overly sensitive and his body was exhausted. At this point he’d fallen asleep a few times in the middle of Steve fucking him and he’d woken up a few times with Steve pounding into him where he was sprawled out on his belly.

Steve’s knot slipped past his rim and swelled up, pushing against his tender insides, before warmth flooded his ass and Steve kept rutting up against him. “Fuck you full.” Tony floated on the pleasure of another knot, “Breed you.” Now Steve nuzzled him and practically rumbled with satisfaction.

A warm hand moved under and rubbed against the small swell of his stomach where Steve’s countless knots had started to become more than obvious.

The sound of the door opening and closing had Tony turning his head. He could feel Steve tense where he was pressing Tony to the mattress. Soon enough the familiar scent of his mate caught his attention, it was a miracle he could smell anything past Steve, and Tony blinked when Bucky stepped into the room.

Steve relaxed and resumed rutting up against his ass without a care.

Tony wasn’t sure if it was because Bucky was a Beta or because Steve’s instincts knew, deep down past the fog of Rut, that the Omega he was locked inside actually belonged to the Beta stepping further into his room.

“Everything ok?”

Bucky’s voice was soft and Tony offed a tired grin when his mate came within touching distance. “Thought you were waiting till Steve was finished.” Tony appreciated Bucky stopping by but he had to tease his mate. “Decide you wanted a good show?”

“This time is a bit different.” Bucky leaned against the nightstand, “I’m sharing you during Steve’s Rut. An Alpha Rut is different. This isn’t Steve tying you up, gagging you and having a good time with your ass. He’s full of Alpha instinct and not completely in control.”

Tony hummed and then cried out when Steve’s knot rubbed repeatedly against his prostate until he was near sobbing with need. He blinked through the haze of pleasure and took in the way Bucky’s eyes had darkened with his own lust.

“Not gonna be able to walk when he’s done.” His voice was rough and wrecked. “Think I might have some bruises.”

“All over your hips, Sweetheart. He’s fucked you good.” Bucky’s eyes moved over what he could see of Tony’s naked body, “How are you doing?”

“A bit fucked out.” Tony groaned when Steve started playing with his neglected cock, “This is a bad Rut. Steve’s probably going to sleep for days when it’s over.”

Bucky nodded and Tony rested his cheek against the sheets. “Do you need anything?”

“No.” he slowly blinked at Bucky, “I’m doing good. Just tired. I’ll probably nap during the next round.” Bucky nodded at him but Tony could see his eyes moving over them and double checking. “I might check back tomorrow. Otherwise just call me when he’s finished and I’ll come get you.”

“Love you.”

“Love you too.”

* * *

The end of the fifth day, mid-fuck, Tony could smell the change in Steve’s pheromones. Steve’s scent slipped into something more familiar and Tony could feel the change in how Steve fucked him.

It was more languid as Tony panted and whined. Now his orgasm was being slowly dragged out of him. It was maddening. Tony yanked at the sheets and shoved back into Steve, trying to encourage him, but Steve held him in place and kept up the slow pace.

“Please, Steve, _please_.”

A low, pleased chuckle sounded behind him. Steve’s pace didn’t change.

It felt like hours that Steve strung him out. Tony almost sobbed in relief when Steve’s knot started to tug on his rim and pleasure shot through him over and over. Finally it sunk in, slipping inside and swelling to lock them together.

Tony’s orgasm slammed into him, stole his ability to breathe and left him shaking as his inner muscles hungrily milked Steve’s knot.

“Fucking asshole.” He muttered when he came down from the high and he could feel Steve grinding up against his ass with pleased, hitching moans of enjoyment.

Steve shifted and a hand lightly swatted him. Tony jerked, his ass clenching down hard, before he swore. It earned a laugh and Steve turned them, pulling Tony snug against his chest, while his knot kept them tied together.

“Shhhh. Sleep.” Steve’s breath ghosted against him and Tony could feel exhaustion tugging him towards sleep. He gave into the warmth and let himself slip off into an uninterrupted sleep.

It was dark when he opened his eyes and shifted, feeling his plug nestled inside of him once more, before blinking at the light spilling into the room from the cracked bathroom door.

“Tony?”

“Hmmm?” he rubbed at his eyes. “Yeah?”

“I called Bucky and let him know my Rut was over.” Tony could hear Steve moving around, “He should be here soon. Do you need anything?”

“Caffeine and a long bath.”

Steve laughed and the door pushed open. The Alpha stood there in nothing but a towel looking pleased and well rested. Tony thought it wasn’t fair how quickly Steve could bounce back when Tony wanted to drown himself in a pool of coffee.

He didn’t move as Steve dressed and left the room when they both heard the front door open before closing. Tony simply laid there listening to the low sound of talking that was steadily getting louder the closer they came to Steve’s bedroom.

“Thanks for sharing him during my Rut. I just—”

“You don’t have to explain. I knew he’d be fine with you.”

“It didn’t bother you? Knowing it was a Rut instead of—”

“No. You’re my best friend, Stevie. It doesn’t bother me when it’s you.”

Tony shifted up on the bed and groaned lowly when his sore ass pressed against the mattress. A glance down revealed that Steve had cleaned him up while he was resting and had apparently changed the sheets.

He wasn’t going to ask.

“Hey.” Bucky’s voice had him looking up, “Caffeine?” he raised his hand and Tony stared at the coffee his mate was holding. “I thought you could use this.”

“I really fucking love you.”

It earned him nothing but laughter. Tony didn’t care because Bucky was handing over the coffee and Tony was gulping it down without a thought. He moaned in enjoyment and sighed as Bucky pulled him in for a kiss.

**Author's Note:**

> A bit different from some of my other fics but hopefully just as enjoyable. Since the square was "consensual partner sharing" I focused on that aspect and I realized that since I had already established Bucky having shared Tony (completely consensual) with Steve in 'All Options' that a follow up could work for my last bingo square needed for a W-shaped bingo.
> 
> I kind of loved exploring a more unconventional look at ABO dynamics (these three combined basically make a perfect Alpha/Beta/Omega triad) and I loved the idea that Bucky and Steve hare everything.
> 
> I hope you all have enjoyed at least one of my bingo fics. This has been a very interesting experience and I've had a blast trying to create a fic to fit each bingo square.
> 
> I'd love to hear what you thought of this one! We'll see if I might try for a blackout because there are still some very interesting square that were not part of this initial bingo.


End file.
